The present invention relates to the use of fans in industrial applications such as exhaust fans and fans associated with various industrial processes. The invention further relates to the measurement of operational fan efficiency and more particularly to the measurement and display of fan efficiency independent of flow rate measurement or of input shaft horsepower.
The measurement of pressure differential has at various times been used to calculate flow rate through fans and the use of brake horsepower, shaft input horsepower and static pressures to evaluate fan performance have been documented. Nonetheless, there exists a need for a simple portable or fixed unit which can measure selected parameters on a substantially instantaneous and incremental basis to determine and display fan efficiency without in any way affecting the fan performance and without requiring knowledge of the specific fan input horsepower or other mechanical characteristics.